Fix disable flag for application conf block

Currently the mere presence of 'disable=xx' disables the application.
Even the 'disable=false', which imho can be confusing. Instead treat it as a boolan

src/libopensc/dir.c

@@ -98,7 +98,7 @@ parse_dir_record(sc_card_t *card, u8 ** buf, size_t *buflen, int rec_nr)
 		sc_bin_to_hex(aid.value, aid.len, aid_str, sizeof(aid_str), 0);
 		blocks = scconf_find_blocks(card->ctx->conf, conf_block, "application", aid_str);
 		if (blocks)   {
-			ignore_app = (blocks[0] && scconf_get_str(blocks[0], "disable", 0));
+			ignore_app = (blocks[0] && scconf_get_bool(blocks[0], "disable", 0));
                         free(blocks);
 		 }